Conventionally, power is generated using portable-type power generation devices using a solar power generation panel and the like, and small-size electronic devices such as cellular phones are charged.
However, in power generation devices used for individuals, there are many cases where the amount of generated power is small, and the stability is low, and thus, there is no device capable of sufficiently supplying power that is consumed by electronic devices such as a cellular phone, a portable music player, a notebook-type personal computer, and a game device of which the number continuously increases, and such devices are mainly used for a secondary use.
In contrast to this, a method of charging a secondary cell of a cellular phone by transmitting power-transmitting microwaves from a wireless base station has been considered (for example, see patent Document 1).
In addition, a method has been considered in which an antenna that irradiates electromagnetic waves is installed, and power is supplied in a wireless manner in a predetermined space near the antenna (for example, see patent Document 2).
Furthermore, a method has been considered in which the output of each electric power device is controlled based on remaining power of a plurality of electric power devices connected to a system (for example, see patent Document 3).